Railway signaling system



Nov. 2, 1937. w. H. REICHARD RAILWAY SIGNALING SYSTEM Filed Dec. 28, 1935 INVEN 10%.

patented Nov. 2, i937 RAILWAY SIGNALING SYSTEM Wade ll-I. Reichard, Rochester, N. Y., assignor to. General Railway Signal Company, Rochester,

Application December 28, 1935, Serial No. 56,488

12 Claims.

This invention relates in general to railway signaling systems, and more particularly to the trackway portion of a combination wayside and cab signaling system for railroads.

It is generally proposed in accordance with the present invention to provide an organization of wayside circuits and apparatus in a railway signaling system whereby wayside signals having at least three distinctive indications are controlled and whereby these signals are energized only when approached by a train, all without the use of control line circuits. It is further proposed to include in such a wayside signaling system means for applying cab signal controlling energy to the track in accordance with forward traffic Other objects, purposes and characteristic fea- ,tures of the present invention will be apparent as the description thereof progresses, during which references will be made to the accompanying drawing which illustrates'in a diagrammatic and conventional manner one specific form of the present invention.

A portion of a railway system has been illustrated in the accompanying drawing as divided by insulating joints J into track sections or blocks I, 2 and 3, and inasmuch as the apparatus is the same for each block, the same reference character will be used to designate like pieces of apparatus at the different blocks with an exponent corresponding to the particular block with which it is associated. The block 3 has been shown as occupied by a train represented by a single pair of wheelsand axle 5, which train carries the usual cab signaling equipment which is illustrated diagrammatically as receiving inductors 6 and I, one carried over each rail, which inductors are inductively energized by alternating current impulses flowing in the rails and this energization is amplified by the usual amplifier A to energize the relay MB. The relay MR when efiectively energized closes front contact 8 to light a clear signal lamp TC and when the alternating current impulses are not flowing in the track rails, the relay MB is deenergized to; close back contact 8 and light the restrictive signal lamp TD, all in a manner obvious from the drawing.

'Wayside signals of any suitable type are located at the entrance of each block, which signals have been illustrated as the color light type having a green clear light G, a yellow caution light Y, and a red danger light R. These wayside signals are controlled in accordance with the character of energization of the associated track circuit which is reflected by the condition of two home control relays HF and HE and a distant control relay D, and these signals are normally deenergized except when an approaching train drops an approach lighting reIay V controlled by the rear ad jacent track circuit as will be later described. I

The apparatus for selecting the character of the track circuit energization at the-exit end of each block comprises an interrupter or coder C of the usual type having a motor (not shown) of a constant speed type arranged to operate contacts designated as ClBi] and C15 at different rates, or for example, it will be considered that contact Cltil is operated at a rate of 180 times per minute and contact C15 at times per minute. A code repeating relay CP is provided to repeat the operation of either contact Cl or C15 according to the condition of the home relays HF and HE as will be later described. A battery B is connected across the exit end of each section through a front contact of the code repeating relay CP, which battery B supplies direct current energy flowing through the rails of the associated track section in series to operate a code following track relay CT connected across the rails at the entrance end of each section. In this manner, the usual direct current coded track circuits are providedin which the code following track relays CT are normally operated in synchronism with the associated code repeating relay CP which is in turn operated at either of two rates by the associated coder 0. I

The impulses of alternating current which are received by the car carried inductors Band I must of course be applied at the exit end of the track sections, and in the present system this alternating current energy is derived from a transmission line l0 extending along the trackway and energized from a generator GE which 40 provides a distinctive frequency'such as cycles per second. The primary of a transformer TA at the exit end of each section is selectively connected across this transmission line Ill according to the condition of the home relays HF and HB 45 7 H13 as will be obvious from the following descrip- '55,

tion of the control of HF and HB relays. The code repeating relays CP is operated over a circuit from the terminal of a suitable source of direct current energy, through coder contact C75, back contact i2 of relay HF through the windings of GP, to whereby the armature of relay CP- is operated at the rate of '75 times per minute.

The battery B is thereby intermittently connected across the rails of section 2 through the usual series resistor S and the windings of the A. C. relay V but these V relays are of the alternating current induction type so that this direct current dos not affect the operation of their armatures. These current impulses of the 15 code rate howeverflow through the track rails in series to cause the armature of the code repeatihg track relay CT to operate at the rate of '75 times per minute. When the code following track relay GT is energized, the home relay HF is picked up through front contact l3, and when deenergized the home relay HE is picked up through backcontact l3 and front contact M of relay HF, and as indicated on the drawing, these home relays HF and HB areof the slow releasing type whereby their armatures are retained in their attracted position during the intermittent periods of deenergization of their windings.

A decoding transformer TC is provided at each block with different portions of the primary alternately energized with direct current by a contact of the associated code following track relay CT to provide an alternating current secondary voltage of a frequency corresponding to the rate of operation of the associated code following track relay. This alternating current voltage of the secondary of transformer TC flows through a tuning circuit represented by a condenser M and a tapped inductance L so arranged as to pass an amount of current to a full wave rectifier K which is effective to pick up the associated D relay only when the frequency of the secondary voltage of the transformer TC corresponds to the 180 code rate of operation of the track relay CT.

Inasmuch as the track relay CT in block 2 is operated at the '75 code rate as previously described, the energization of transformer TC changes at the rate of 75 times per minute, this energization being from through front contact l6 of relay GT through one half of the primaryof transformer TC to through a center tap, which circuit is shifted by the closing of back contact l6 to the other half of the primary winding. This alternate primary energization produces an alternating flux to induce an alternating current in the secondary of transformer T of '75 cycles per minute. This frequency is tuned out by the selected values of condenser M and inductor L so that the voltage impressed on the full wave rectifier K by a tapped portion of inductor L is not sufficient to atract the armature of relay D It will be clear however, that if the armature of relay CT were operated at the 180 code rate, this tuning arrangement would be in resonance to provide an output suiflcient to attract the armature of relay D and such a condition would exist at all unoccupied blocks in the rear of block 2.

In order to provide normally deenergized wayside signals, alternating current energy is superimposed on the track circuits at the entrance end of each section, or a transformer TB is provided with its primary energized from a suitable source of alternating current such as from the power line and with its secondary connected across the rails at the entrance end of the associated sec tion in series with the usual series impedance RS. The current from the secondary of transformer TB flows through the rails in series to energize the associated alternating current relay V when a front contact of the associated code repeating relay CP is closed, and through the associated track battery B. When the associated track section is unoccupied, the V relay is intermittently energized due to the oscillation of the associated code repeating relay CP, and these V relays are sufficiently slow releasing that their armatures remain in their energized position during such intermittent energization.

When, with the apparatus of the present system in its illustrated condition, a train enters section I, it will be clear that the alternating current energy applied at the entrance end of section I by a transformer TB (not shown) will be shunted away from relay V thus causing its armature to be released, whereupon the yellow signal lamp Y will be energized from front contact I8 of relay HB front contact l9 of relay HF back contact 20 of relay D through the yellow light Y andthrough back contact 2| of relay V to Likewise it will be clear that the primary of transformer TA is connected across the line wires l0 through front contacts 24 and 25 of relays HB and HF respectively, so that alternating current from the secondary of transformer TA is applied to the exit end of section I through back contact 21 of relay CP A1- ternating current impulses are thereby applied to the exit end of the track circuit of section I of the 180 code rate due to the operation of the code repeating relay CP by the contact C|80 of coder C through front contacts 29 and 30 of relays HB and HF respectively. The receiving coils of the present train traversing section I are inductively energized by the alternating current impulses to energize the car carried control relay and light the clear cab signal lamp, thereby indicating on the train that sections 1 and 2 are unoccupied.

When the present train approaches section 2, the energization of the yellow signal lamp Y indicates that section 2 is unoccupied but that section 3 may be entered only at minimum speed, and inasmuch as relays HF and HB are both deenergized, there are no impulses of alternating current applied to the exit end of section 2 due tol open front contacts 32 and 33, and consequently a restrictive cab signal indication will be displayed when this train enters section 2. However, if the forward train illustrated as occupying section 3 progresses out of section 3 during the time that the rear train now under consideration is traversing section 2, it will be clear that the home relays HB and HF will pick up to energize the primary of transformer TA through front contacts 32 and 33 thereby supplying alternating current impulses to the exit end of section 2. In this manner the restrictive cab signal indication on. the rear train will be changed to a clear indication to inform the engineer that section 3 has become less restrictive thereby allowing the speed of the rear train to be accordingly increased.

In this manner a signal system has been provided wherein coded track circuits are employed to provide the distant control of Wayside signals according to the rate of direct current track circuit impulses to thereby avoid the use of control line Wires, and these direct current impulses are separated by impulses of alternating current to of track sections, means for applyingdirect cur- 1 rent impulses separated by alternating current impulses tothe exit end of each section, means selecting the rate of said impulses in accordance provide the track circuit energy used to condition car carried cab signals or train control apparatus. The track circuits of the present system havebeen furthen utilized to provide the approa'ch lighting of the wayside signals also to avoid the use of control line wires, by means of a source "of altern'ating current energy superimposed on the direct current coded track circuit to control an alternating current relay at the exit ,end of each section. This relay is energized during the periods in which direct current is applied at the exit end for the distant control of the wayside signals and until the entrance of a train into the track section shunts the track from transcurrent.

An important feature of such an arrangement is of course the control of three indication wayside signals as well as the approach lighting of these wayside signals all without the use of control line circuits. It will also be apparent that the combination of coded direct current track circuit impulses separated by alternating current impulses for a cab signal control provides a feature wherein wayside signals can be supplemented by a cab signal system to obtain the well recognized advantages of such a combination with a minimum amount of additional apparatus.

The above rather specific description of one form of the present invention is given solely by the way of example, and is not intended. in any manner whatsoever, in a limiting sense. It is also to be understood that various modifications, alterations and adaptations may be applied to the particular form shown without departing from the spirit or scope of the present invention, except as limited by the appended claims.

What I claim is:--

1. In a railway signaling system, a plurality of track sections, means for applying spaced direct current impulses to the exit end of each section, means selecting the rate of said impulses in accordance with trafiic conditions, a track relay at the entrance of each section operated by the direct current impulses, wayside signals at each section, means for controlling the wayside signals in accordance with the rate of operation of the associated track relay, a source of alternating current connected at the entrance end of each section, and an alternating current relay intermittently connected to the exit end of each section for controlling the energization of the associated wayside signal.

2. In a railway signaling system for wayside signals and for inductively controlling cab signals by alternating current impulses, a plurality of track sections, means for applying direct current impulses and alternating current impulses to the exit end of each section, means selecting the rate of said direct current impulses in accordance with trafiic conditions, a track relay at the entrance end of each section operated by the direct current impulses, wayside signals at each section, means for controlling the wayside signals in accordance with the rate of operation of the associated track relay, an alternating current track circuit superimposed on each section, and means controlled by the alternating current track cuit for approach lighting the associated wayside signal the alternating current impulses separating the direct current impulses whereby to prevents such alternating current impulses from operating the approach lighting means.

3. In a railway signaling system, a plurality with tramc conditions, car carried means controlled by the alternating current impulses, a'

track relay at the entrance of each section operated by the direct current impulses, wayside signals at each section, and means for controlling the wayside signals in accordance with the rate of operation of the associated track relay.

4. In a signaling system for railroads, a plurality of insulated track sections, wayside signals at each track section, a source of direct current and a source of alternating current at each section, means alternately connecting the source of direct current and the source of alternating current to the exit end of each track section, means selecting the rate at which the sources of direct and alternating current are alternately connected to the track sections in accordance with trafilc conditions, car-carried sig-,

naling means controlled by the alternating current, a track relay at the entrance end of each section operated by the source of direct current, and wayside signal controlling means controlled by the operation and rate of operation of the associated track relay.

5. In a signaling system for railroads for wayexit end of each track section, means selecting the rate at which the source of direct current is alternately connected to the track sections in accordance with trafiic conditions, car-carried signaling means governed in accordance with the presence or absence of such alternating current impulses, a track relay at the entrance end of each section operated by the source of direct current, wayside signal controlling means controlled by the operation and rate of operation of the associated track relay, an approach control relay responsive to alternating current only in series with the source of direct current at each section for controlling the energization of the associated wayside signals, and a source of alternating current connected to the entrance end of each section for normally energizing the associated approach control relay.

6. In a signaling system for railroads, a plurality of insulated track sections, wayside Signals at each section, contact means at each section oscillating at either of two rates according to forward traffic conditions, a source of direct current connected to each track section through a front point of the associated contact means, a track relay at each section operated by the associated source of direct current, home signal control relays at each section controlled by the operation of the associated track relay, a distant signal control relay at each section controlled by the rate of operation of the associated track relay, and a source of alternating current selectively connected to the exit end of each track section through a back point of the associated contact means in accordance with forward traflic conditions whereby to condition car carried cab signals.

7. In a signaling system for railroads, a plurality of insulated track sections, wayside signals at each Section, contact means at each section oscillating at either of two rates according to forward traffic conditions, a source of direct current connected to each track section through a front point of the associated contact means, a track relay at each section operated by the associated source of direct current, home signal controlrelays at each'section controlled by the operation of the associated track relay, a distant signal control relay at each section controlled by the rate of operation of the associated track relay, and a separate source of cab signal controlling current selectively connected to the exit end of each track section through a back point of the associated contact means.

8. In a railway signaling system having a plurality of track sections, a direct current track relay at the entrance end of each section, an oscillating contact means at the exit end of each section operable at different rates according to forward traffic conditions, a source of direct current connected to each track section through a front point of the associated oscillating contact means, wayside signal controlling means at each section controlled according to the rate of operation of the associated track relay, and a source of alternating current selectively connected to the exit end of each section through a back point of the associated oscillating contact means in accordance with trafiic conditions whereby to inductively control cab signaling means.

9. In a railway signaling system, a plurality of insulated track sections, coding means operable to intermittently energize each track section with direct current impulses of distinctive code characteristics in accordance with traffic conditions, a direct current track relay at each section operated by the direct current impulses, decoding means associated with each track relay and responsive to the character of the code impulses energizing that relay, wayside signals controlled by the decoding means, means energizing each track section with alternating current'impulses alternating with the direct current impulses, and signal means inductively con- 'trolled by the alternating current impulses.

10. In a railway signaling system, a plurality of track sections each including a direct current coded track circuit, an alternating current relay at one end of the track circuit in series with the direct current track circuit, a source of alternating current at the other end of the track circuit intermittently energizing the alternating current relay, and wayside signals at the entrance to a given track section controlled by the direct .current coded track circuit of that section and the alternating current relay of the next track section in the rear. i 11. In a signaling system for railroads, a plurality of insulated track sections, wayside signals at each track section, a source of direct current and a source of alternating current at each section, means connecting the source of direct current and the source of alternating current to the exit end of each track section, means selecting the rate at which the sources of direct and alternating current are alternately connected to the track sections in accordance with trafiic conditions, a track relay at the entrance end of each section operated by the source of direct current, car-carried cab signaling means controlled by the alternating current, and wayside signal controlling means controlled by the operation and rate of operation of the associated track relay.

12. In a signaling system for railroads, a plurality of insulated track sections, wayside signals at each track section, a source of direct current and a source of alternating current at each section, means connecting the source of direct current and the source of alternating current to the exit end of each track section, means selecting the rate at which the source of direct current is connected to the track sections in accordance With trafic conditions, cab signals controlled by the alternating current, a track relay at the entrance end of each section operated by the source of direct current, wayside signal controlling means controlled by the operation and rate of operation of the associated track relay, an approach control relay responsive to alternating current only in series with the source of direct current at each section for controlling the energization of the associated wayside signals, and a source of alternating current connected to the entrance end of each section for normally energizing the associated approach control relay.

WADE H. RAEICHARD. 

